The specific aim of this research program is to develop and transition a low-cost, liquid oxygen (LOX) generation system to support ambulatory patients using Home Oxygen Therapy (HOT). Currently in the United States, yearly expenditures on HOT are nearly two billion dollars. These expenditures will increase dramatically over the next 10 years due to the aging baby-boomer generation. The increase in use of LOX-based HOT systems is expected to continue due to demographics, patient and clinician preferences, and the general success of HOT as a treatment regimen. The primary drawback of LOX-based systems is the high-operational cost, because the storage reservoir for these systems must be refilled with LOX frequently. Creare's innovation is a Miniaturized LOX Generation System (MLGS). This novel device is a small, low-power, low-cost system that generates liquid oxygen from atmospheric air. The basis of the innovation is the miniaturization of the liquid oxygen systems we have developed for the military. Our novel system will directly refill the portable LOX unit, eliminating the need for the storage reservoir, and the LOX re-supply infrastructure. Thus, our innovation will substantially reduce the cost of LOX-based HOT, while improving convenience, safety, and compliance.